Publications (17)
Pulsation models for the 0.26M_sun star mimicking RR Lyrae pulsator. Model survey for the new class of variable stars
R. Smolec, G. Pietrzynski, D. Graczyk +11
We present non-linear hydrodynamic pulsation models for OGLE-BLG-RRLYR-02792 - a 0.26M_sun pulsator, component of the eclipsing binary system, analysed recently by Pietrzynski et a…
Effective temperatures of magnetic CP stars from full spectral energy distributions
L. Lipski, K. Stepien
New determinations of effective temperatures of 23 magnetic, chemically peculiar (mCP) stars were obtained from a fit of metal enhanced model atmospheres to the observed spectral e…
ASAS Photometry of ROSAT Sources. II.New Variables from the ASAS North Survey
M. Kiraga, K. Stepien
We present a catalog of 307 optical counterparts of the bright ROSAT X-ray sources, identified with the ASAS North survey data and showing periodic brightness variations. They all…
The empirical upper limit for mass loss of cool main sequence stars
Anna Lednicka, K. Stepien
The knowledge of mass loss rates due to thermal winds in cool dwarfs is of crucial importance for modeling evolution of physical parameters of main sequence single and binary stars…
RR-Lyrae-type pulsations from a 0.26-solar-mass star in a binary system
G. Pietrzynski, I. B. Thompson, W. Gieren +14
RR Lyrae pulsating stars have been extensively used as tracers of old stellar populations for the purpose of determining the ages of galaxies, and as tools to measure distances to…
Ultra-Short-Period Binary Systems in the OGLE Fields Toward the Galactic Bulge
I. Soszynski, K. Stepien, B. Pilecki +11
We present a sample of 242 ultra-short-period (P < 0.22 d) eclipsing and ellipsoidal binary stars identified in the OGLE fields toward the Galactic bulge. Based on the light curve…
Evolution of Low Mass Contact Binaries
K. Stepien, K. Gazeas
We present a study on low-mass contact binaries (LMCB) with orbital periods shorter than 0.3 days and total mass lower than about 1.4 solar mass. We show that such systems have a l…
Evolution of the progenitor binary of V1309 Scorpii before merger
K. Stepien
It was recently demonstrated that the eruption of V1309 Sco was a result of a merger of the components of a cool contact binary. We computed a set of evolutionary models of the det…
Angular momentum and mass evolution of contact binaries
K. Gazeas, K. Stepien
Various scenarios of contact binary evolution have been proposed in the past, giving hints of (sometimes contradictory) evolutionary sequence connecting A-type and W-type systems.…
Large scale circulations and energy transport in contact binaries
K. Stepien
A hydrodynamic model for the energy transport between the components of a contact binary is presented. Energy is transported by a large-scale, steady circulation carrying high entr…
The Low-Mass Limit for Total Mass of W UMa-type Binaries
K. Stepien
The observations of W UMa type stars show a well-defined short-period limit of 0.22 d, which is equivalent to a lower mass limit of approximately 1 solar mass for the total binary…
Evolution of Cool Close Binaries - Approach to Contact
K. Stepien
A set of 27 evolutionary models of cool close binaries was computed under the assumption that their evolution is influenced by the magnetized winds. Initial periods of 1.5, 2.0 and…
Evolutionary status of late-type contact binaries
K. Stepien
A new scenario for evolution of contact binaries is presented and discussed. Arguments are given that W UMa-type systems are formed from detached binaries which lose angular moment…
Why are magnetic Ap stars slowly rotating?
K. Stepien
Observational data on rotation of Ap stars suggest that the bulk of their rotation rates form a separate Maxwellian distribution with an average value 3-4 times lower than the norm…
Evolutionary history of four binary blue stragglers from the globular clusters ÏCen, M55, 47 Tuc and NGC 6752
K. Stepien, A. A. Pamyatnykh, M. Rozyczka
Context. Origin and evolution of blue stragglers in globular clusters is still a matter of debate. Aims. The aim of the present investigation is to reproduce the evolutionary histo…
Multi-Task Deep Learning for Surface Metrology
D. Kucharski, A. Gaska, T. Kowaluk +9
A reproducible deep learning framework is presented for surface metrology to predict surface texture parameters together with their reported standard uncertainties. Using a multi-i…
Age-Rotation-Activity Relations for M Dwarf Stars Based on ASAS Photometric Data
M. Kiraga, K. Stepien
Based on analysis of photometric observations of nearby M type stars obtained with ASAS, 31 periodic variables were detected. The determined periods are assumed to be related to ro…